This invention relates to tools for establishing guides for placing or pouring concrete and similar work in new concrete construction such as a roadway, driveway, sidewalk, patio or building floor.
In the past it was conventional practice to dig out the ground to a desired depth and then place a string line at the predetermined elevation of the finished concrete surface. Wooden stakes were then driven into the ground and pipes were laid horizontally on top of them. The upper surface of the pipes indicate the desired elevation of the finished concrete. Nails were driven into the stake tops on both sides of the pipe to keep it from rolling or being bumped off. The concrete was then poured or dumped into the desired area and struck or screed off with a strike board or screed on top of adjacent pipes. The pipes may be removed while the concrete is drying or setting and the indentations after removal of the pipes are then filled and the surface smoothed out, thus establishing a finished surface at the desired elevation of the concrete.
The use of wooden stakes with nails at their tops is inefficient, costly and time consuming compared to the material, tools and method of using them in the present invention. Wooden stakes are hard to drive so that their tops are at the required depth below the string line. They must be individually measured from the string line with a tape measure. The wooden stakes split easily when driven into the ground or when driving nails into them for holding the screed pipe. Often the accuracy is lost while driving nails in the stake tops in sand or soft soil conditions. In cold climates the wooden stakes swell in the concrete, causing cracks in the concrete.